Throttle body coolant hoses.

[91CoupeMike]

I asked this once before but never got an answer because i worded it differently.

The EGR coolant lines on a fox, can i bypass those so they dont flow water through the TB? will the EGR gasses over heat the plenum at that point then? or will it be okay?

Im not looking to "gain" power, just seeing if its possible. ive seen cars with no lines, and ive seen cars with the lines capped.

JW.

Thanks.

[sdun]

Pull the upper and plug the small center hole with a freze plug. Then you don't need the coolant lines. Leave them until there is no exhaust gas in the upper.

[mustgofaster]

Pull the upper and plug the small center hole with a freze plug. Then you don't need the coolant lines. Leave them until there is no exhaust gas in the upper.

/\/\ What he said. If you don't plug the EGR passage first you will overheat the TB. The coolant is there to keep the temps from going too high.

[91CoupeMike]

/\/\ What he said. If you don't plug the EGR passage first you will overheat the TB. The coolant is there to keep the temps from going too high.

What advantages and disadvantages would I see from no egr?

[Mike]

Just put some red locktite on that bitch.

[TENGRAM]

What advantages and disadvantages would I see from no egr?

Pros (all of which are debatable):
-possible slight increase in performance due to no heat addition to TB
-possible snappier throttle response due to no exhaust gasses lingering in intake charge when transitioning to WOT
-cleaner underhood appearance (if done right)

Cons:
-Check engine light will remain on unless you reprogram the ECM, tape up the EGR Valve Position Sensor, or use an "eliminator kit"
-More NOx emissions which may fail you come inspection time
-if you do it wrong (eg. plugging the EGR ports and not disabling the EVP sensor) you may have detonation since the EGR function in the ECM increases timing advance when the sensor indicates that your EGR is functioning
-theoretically worse fuel efficiency (this is highly debatable as well)


Bottom line: unless you have some theoretical or experimentally-founded reasoning behind doing it, and unless you know exactly how you are going to affect the ECM programming to compensate for it, don't bother. If it's beneficial at all it is only marginally so. If you sell your car to someone like that you may screw yourself out of a few bucks if they notice it beforehand, or you may screw them when they find out they need it.

[garycrist]

I've been whacking egrs since '74 and used to always get better performance, mileage, etc. Now the systems are integrated and "tuned" for it. I did it on my 92 GT and saw a slight mileage drop. After reconnecting I saw a slight gain. It is now hooked up.

[2cammer97]

I think TENGRAM said it perfect.

I removed mine when I did H/C/I for a cleaner look in the engine bay and since I have an SCT chip I was able to turn off the EGR function and no CEL. You could still fail visual state inspection without the EGR but I'd say that's rare (I haven't had this problem).

Marcus

[noslow5_0]

If your EGR is functioning properly, then just leave it all alone. Ford put the coolant lines there to melt any frost/ice that might have formed in below freezing temps. If you plan to do a h/c/i swap and get it tuned later, then look into removing it for a cleaner look. FWIW, I've always just taped up the pintle in the egr sensor, made a block off plate on the back of the upper intake and tucked the sensor back behind the upper intake. I also run with no evp or any of the EGR selonoids smog pump etc... My h/c/i 302 would pass inspection with flying colors untuned. As long as the motor is in decent shape (no blow by, down on compression, etc etc) and you have a decent set of catalytic converters you will be fine. Just make sure to change the oil before a sniffer test, and as a precaution set the timing back to the base 10*. If you are still unsure if it will pass or not Run the tank almost empty, put some rubbing alcohol in the tank with some 87 octane. It will actually be a more complete burn then higher octane resulting in less emmissions. Just dont romp on the car untill you get some 93 in the tank. It will ping like crazy. Sorry for going off on a tangent... I was in ur shoes 8 years ago with my first fox.

[mustgofaster]

Ford put the coolant lines there to melt any frost/ice that might have formed in below freezing temps.

Nope... Has nothing to do with freezing temps. It is to keep the Throttle body & EGR spacer from overheating due to the hot exhaust gasses circulating through them.

EGR 101... Basically the theory of operation is that you are replacing oxygen with an inert gas, which allows the engine to run leaner @ low HP levels & with more timing, without causing excessive cylinder temperatures from the lean condition. By keeping the cyl temps down, your NOX is reduced, and more timing can be applied without causing pre-ignition.
The Carbon Dioxide in the exhaust is your inert gas. By displacing the oxygen in the atmosphere, you are effectively reducing the volume. Less volume = less fuel needed to maintain the correct AFR.

This is why you cannot just blank it off without making changes to your tune. If your processor is calling for EGR, it will lean out, thinking that it is metering X amount of Gas into the cyl. Then your NOX goes high & your engine will knock.

[broke again]

Nope... Has nothing to do with freezing temps. It is to keep the Throttle body & EGR spacer from overheating due to the hot exhaust gasses circulating through them.

EGR 101... Basically the theory of operation is that you are replacing oxygen with an inert gas, which allows the engine to run leaner @ low HP levels & with more timing, without causing excessive cylinder temperatures from the lean condition. By keeping the cyl temps down, your NOX is reduced, and more timing can be applied without causing pre-ignition.
The Carbon Dioxide in the exhaust is your inert gas. By displacing the oxygen in the atmosphere, you are effectively reducing the volume. Less volume = less fuel needed to maintain the correct AFR.

This is why you cannot just blank it off without making changes to your tune. If your processor is calling for EGR, it will lean out, thinking that it is metering X amount of Gas into the cyl. Then your NOX goes high & your engine will knock.

Was always my understanding the lines were to heat the the tb, not cool it...

[shumpertdavid]

mustgofaster pretty well hit it on egr function. The inert gases help to cool combustion temps and reduce emissions. This is mostly done a highway cruise speeds where there is little load on the engine. You can watch the egr duty cycle on a scanner running down the road and it will go up and down as you throttle up or down from cruise/light load.

It should cause a decrease in fuel mileage on anything that see's regular highway/cruise usage.

As far as the coolant lines go, I assume they help warm up the intake from a cold start to help cut down on emissions and also help control intake temps when the egr is functioning. IIRC the cobra intake has an integrated egr port and doesn't have coolant lines running to it, but it's been a while since I've looked at one.

[mustgofaster]

When the engine is cold, the coolant is cold too, so it won't do much for cold startup. The heat from the exhaust gasses will warm it up long before the coolant comes up to temp.